The invention relates to a transistor oscillator for operation in the microwave band utilizing a basic CLAPP-circuit configuration, which involves a capacitive Hartley three-point circuit having a capacitance disposed in series with the circuit inductance. See for example FIG. 1.
Of the oscillator circuits commonly employed in microwave technology, the CLAPP oscillator offers the best possibilities for a wide-band frequency variation as the circuit inductance L.sub.S can be compensated by the reactance of the series capacitance C.sub.S. With such circuit, the highest oscillating frequency is determined from the value of the collector-base capacitance C.sub.CB and of the smallest circuit inductance. The feedback network comprises the capacitive voltage divider between collector and emitter as well as between emitter and base. With higher frequencies the parasitic emitter-base capacitance C.sub.CE and emitter-base capacitance C.sub.EB can be advantageously utilized as capacitive voltage dividers for the feedback network.